Vindicating conventional wisdom, today’s argument suggested that the Supreme Court will find that states must both recognize and license same sex marriage. That’s remarkable in and of itself considering that a little over a decade ago, we were still debating whether states could criminalize gay sex. But it’s not surprising, given that it represents the most rapid transformation in public opinion on any political issue.

What’s more noteworthy is the reason why the Court is poised to rule this way. While it’s certainly possible that Justice Kennedy will wax metaphysical about the “sweet mystery of marriage,” the majority opinion is more likely to rest on the technical requirements of the Equal Protection Clause. Given that provision’s enforcement of “equality under the law,” states simply cannot devise a reason to draw their marriage licensing regimes in a way that distinguishes between heterosexual and homosexual couples.

Solicitor General Don Verrilli said it best – that’s possibly the only time I will use those words – when he asked the Court to secure “equal participation in a state-conferred status.” Moreover, the federal government was wise here – again unprecedented words coming from me – in focusing on the narrow point of equality in the application of state laws.

In sum, the Supreme Court should – and likely will – stay away from pontificating about marriage or philosophizing on the nature of rights. The Fourteenth Amendment is silent as to marriage, as it is regarding all other possible objects of state regulation. What it speaks to instead is the equal protection of the laws. Accordingly, as Cato said in our amicus brief, states must give marriage licenses to gays and lesbians only if they give them to everyone else.